Java SE technology

Sep 9 posted in Java (RSS), comments.

What is Java technology?

Java technology is both a high-level object-oriented programming language, but also a platform. Java technology is based on the Java Virtual Machine (Java virtual machine, JVM) concept - this is the language and the underlying software and hardware of a converter between. Java language must be to achieve the realization of all the JVM, so that the Java program can have a JVM running on any system.

Java programming language (Java programming language) is that different: Java is a compiler-based program (compiled) (converted to a Java byte code as the intermediate language), but also interpreted the (interpreted) ( JVM byte code to parse and run). Compiled only once, and explain the procedures for each operation will be carried out. Byte-code compiled for the JVM uses a binary format optimized; interpretation is the realization of JVM.

Java platform (Java platform) is a pure software platform, which can in a variety of hardware-based platform. There are three versions of it (see the back of multiple versions of Java platform ). It consists of JVM and Java Application Programming Interface (Java Application Programming Interface, API) component. Java API is a large off-the-shelf software components (type of) the collection, which can simplify the applet and application development and deployment, including robust, secure and interoperable enterprise applications. It covers from basic objects to the Internet and security, to XML and Web services to generate everything. Organized into Java API classes and interfaces related to the base; Treasury package also known as the (package).

Apart from the Java API, each complete Java platform also includes:

Used to compile, run, monitor, debug applications, and documents to establish the application development tools.
Applications for the deployment of the standard mechanisms.
Used to create complex graphical user interface (GUI) user interface toolkit.
Used to enable remote access and manipulate database objects of the integrated library.

Java technology is initially developed by Sun Microsystems. Java Community Process (JCP, a world of Java developers and staff have obtained approval for an open organization) on the Java specification, Reference Implementation and Technology Compatibility package for the development and revision. In August 2006, Sun Microsystems announced its intention to open source Java platform, and began consulting on licensing agreements and management feedback.

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Java technology is important why?

Java's main advantage is the language, Java applications across hardware platforms and operating systems for transplant - This is because the platform is installed on each of the JVM can understand the same byte code.

Java language and platform scalability is very strong. In the low-end, existing applications can easily adapt to the device memory resources are limited. This language is a server-side Web programming framework for the ideal. Because it is designed for a safe manner in accordance with a run through the network, in operation through the Internet, which provides a degree of security. In essence, Java technology will be the user's computing power to expand from the desktop to the Web resources. Web components called Web containers (Web container) of the run-time platform support, Web services, including the request of containers assigned, security, concurrency, life cycle management, as well as name and e-mail and other services visit API. In the high-end, Java application server (application server) as Java components, XML and Web services, Web container, you can interact with the database and to provide dynamic Web content; They also applications for the enterprise application development environment, with Services management, security, clustering, performance, availability, connectivity and scalability features.

Java language is the first open standards in support of enterprise technologies, support the use of XML and Web services to share information across business lines and applications (see the following Java technology and SOA / Web services, the relationship between ). Java technology is the number of IBM products and technical advisory services to the core (see the following Java programmers available to IBM tools and products ), IBM is an important part of development plans:

Learn more about IBM's service-oriented architecture (SOA) Plan For more information, as well as how SOA helps users build composite applications, which will come from the combination of features from multiple sources in the enterprise to support horizontal business processes.
IBM Business Innovation and Optimization To provide a strategic adjustment of component-based comprehensive approach. The solution is based on providing a flexible, scalable, open standards-based software (including Java technology) and hardware infrastructure.

- Multiple versions of Java platform there are three versions of Java platform, which makes software developers, service providers and equipment manufacturers can develop a specific market:
  - Java SE (Java Platform, Standard Edition). Java SE, formerly known as J2SE. It allows the development and deployment of the desktop, server, embedded and real-time environment of Java applications. Java SE includes support for the development of Java Web services category, and Java Platform, Enterprise Edition (Java EE) provides the basis. The majority of Java developers use Java SE 5, also known as Java 5.0 or "Tiger" (2006 on 6 years, Java SE 6 or "Mustang" release of the beta version.)
  Tiger tamed
  Column on the Java SE 5 has done a wonderful overview.
- Merlin's Magic Series of discussions the previous version of the Java SE platform, J2SE 1.4 or "Merlin". Many existing Java applications based on J2SE 1.4, but the majority of this series is the concept of Java SE 5 programming related.
Java EE (Java Platform, Enterprise Edition). This version formerly known as J2EE. Enterprise Edition to help develop and deploy portable, robust, scalable and secure server-side Java applications. Java EE is based on the Java SE built, which provides Web services, component model, management and communication API, can be used to achieve enterprise-class service-oriented architecture (service-oriented architecture, SOA) and Web 2.0 applications procedures.
- J2EE Explorer Columns provide information on the Java EE knowledge.
- Onto the open road: moved to the Java platform Article series to help. NET, Windows client / server and ASP application developers moved to the Java EE platform.
Java ME (Java Platform, Micro Edition). This version formerly known as J2ME. Java ME for mobile devices and embedded devices (such as mobile phone, PDA, TV set-top boxes and printers) to run the application to provide a robust and flexible environment. Java ME includes flexible user interface, robust security model, and many built-in network protocols and dynamically download the Internet and offline applications in support of the rich. Java ME-based application specification prepared only once, can be used on many devices and each device can make use of local features.
- This comprehensive Four-part series Contains two tutorials and two supporting article, they focus on J2ME and Mobile Information Device Profile (MIDP).
- Can developerWorks Wireless technology J2ME area to find many references, such as two parts of the curriculum " J2ME to build a flexible mobile application . "

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What is a Java component technologies?

developerWorks Java technology area to maintain a standard Java component technology A complete glossary. The following Java platform versions of each component, optional packages and expansion of part of the list, as well as a brief description and links to reference materials, reference materials through a better understanding of these of these components in the Java development role. Note that many of the following references for three versions at the same time.

Java SE technology:
"; Guide" Java security, Part 2: Authentication and Authorization "Also helped.)

Java Cryptography Extension (JCE) is a group of packages, which provide for encryption, key generation and consultations as well as the Message Authentication Code (MAC) algorithm and the realization of the framework. It provides for the symmetric, asymmetric, block and stream cipher encryption support, it also supports the security of the target flow and sealing. (See tutorial " Java security, Part 1: Cryptography based on . ")

Java Data Objects (JDO) is a standards-based Java persistence interface abstract model, so that Java programmers can be an example domain model directly into the persistent storage memory (database), which can substitute for direct file I / O, serial of, JDBC and EJB Bean Managed Persistence (BMP) or Container Managed Persistence (CMP) entity bean methods. (See tutorial " Java Data Objects Hands-on practice "; A more in-depth explanation please refer to" No object-relational mapping containers . ")

Java Management Extensions (JMX) to provide for building distributed, based on the Web, modular and dynamic applications, tools, these applications can be used to manage and monitor devices, applications and service-driven networks. (See " Management bean using the Java platform . ")

Java Media Framework (JMF) can be audio, video and other time-based media added to the Java application and applet in. (See tutorial " Java Media Framework basics . ")

Java Naming and Directory Interface (JNDI) for Java applications to connect to the enterprise in a number of naming and directory service interface, you can seamlessly connect the structure of different naming and directory services business. (See " JNDI optimization of industrial strength "; Also can refer to" Out of JNDI maze . ")

Java Secure Socket Extensions (JSSE) is a group of packages, their support for secure Internet communications, the realization of the SSL (Secure Sockets Layer) and TLS (Transport Layer Security) version of Java, including data encryption, server authentication, message integrity and optional client authentication functions. (See " JAAS and JSSE with the realization of Java security "; Also can refer to Guide" Will JSSE for Secure Socket Communications . ")

Java Speech API (JSAPI) contains Grammar Format (JSGF) and Markup Language (JSML) specification, so that Java applications can be integrated voice technology to the user interface. JSAPI define a cross-platform API, support for command and control recognizers, dictation systems and voice recognition. (See " Java 2 user interface . ")

Java 3D is an API, it provides a set of object-oriented interface, such a simple interface to support high-level programming model, developers can use this API to easily scalable platform-independent 3D graphics into Java applications in. (See tutorial " Java 3D exploring . ")

Metadata FacilityAllow to type, interfaces, fields and methods marked with specific attributes, so that the development tools, deployment tools and run-time library in a special way to dealing with them. (See " Tiger of the Notes, Part 1: Java code to add meta-data . ")

Java Content Repository API is a Java SE is used to access independent of the realization of the contents of the repository API. Content repository is an advanced information management system, it is the repository of traditional data superset. (See " About Java Content Repository API . ")

Enumerations (enumeration) is a type, allowing type-safe way to be specific for the constant data. (See " Enumeration type entry . ")

Generics (generic) to allow the definition of abstract types with type parameters can be specified in the instantiation of these parameters. (See " JDK 5.0 introduced the generic . ")

Concurrency Utilities is a set of intermediate utility, providing concurrent programming features in common. (See tutorial " Concurrency in JDK 5.0 . ")

Java API for XML Processing (JAXP) allows Java applications independent of the specific processing of XML documents to XML parsing and conversion, XML allows the flexibility to switch between processes, without having to modify application code. Java API for XML Binding (JAXB) allows XML documents and Java automatic object mapping between. (See the three parts of the curriculum " The use of Java technology, XML Programming "; Also can read" A comprehensive introduction to JAXP, Part 1 "And" A comprehensive introduction to JAXP, Part 1 "To learn more about JAXP; Practical data binding The article series will provide more information; also be able to access developerWorks XML Area. )

SOAP with Attachments API for Java (SAAJ) enables developers to in accordance with the SOAP 1.1 specification and SOAP with Attachments note message generation and consumption. (See " Skills: Use SAAJ to send and receive SOAP messages ";" Advanced Java Web Services "Will help you master the Java Web Services Developers Pack.)

J2EE technology:

Enterprise JavaBeans (EJB) component model using a technique to simplify the development of middleware applications, it provides services, security and database connectivity and other services to support the automatic. (See tutorial " The basis of Enterprise JavaBean "; See EJB best practices Series; read " The use of EJB 3.0 Java Persistence API design of enterprise applications . ")
Portlet Specification defines a set of calculations for the Java Portal API, polymerization can be solved, individuals, and that and safety issues. (See " Apache Pluto used to build and test JSR 168-compliant portlets . ")
JavaMail is an API, to provide a set of e-mail system for the abstract class model. (See tutorial " JavaMail API Essentials . ")
Java Message Service (JMS) is an API, for all its technology compatible with the JMS messaging system definition of the concept of a common set of information and programming strategy to support the development of portable Java-based news application. (See tutorial " Java Message Service introduced . ")
JavaServer Faces (JSF) provides a programming model to help developers to reusable UI components in page composition, these components will be connected to the application data sources, will be client-generated events to connect to the server-side event handler, so easy to set up Web applications. (See Skeptics of the JSF Columns and tutorials " UI used to carry out the development of JavaServer Faces "And JavaServer Faces technology topics . )
JavaServer Pages (JSP) allows Web developers to rapidly develop and easily to maintain a dynamic platform-independent Web page, and will generate the user interface and content separated, so that designers can modify the page layout without having to modify dynamic content. The use of this technology similar to XML tags to package content for the page to generate logic. (See tutorial " Introduction to JSP technology "; Also please refer to JSP best practices Series, as well as JavaServer Pages technology topics . )
Standard Tag Library for JavaServer Pages (JSTL) is a collection of custom tags, which in a standardized format to enable many common Web site functions. (See " JSP using JSTL to update the page "And the four parts of the article series" Introduction to JSTL . ")
Java Servlets provide a component-based platform-independent way to build Web-based applications, while avoiding the performance limitations of CGI program to expand and enhance Web server functionality. (Guide " Java Servlet Technology "Can help you understand the Java Servlets.)
J2EE Connector Architecture(JCA) for the J2EE platform to connect to a variety of the structure of Enterprise Information Systems (EIS) defines a standard architecture, which defines a set of scalable business security mechanism so that the standard EIS vendor to provide appropriate resources adapter, you can insert these resources application server adapters. (See " Understanding JCA Services "" EAI choice for the JCA, JMS, or Web services "" Integrate remote enterprise information systems with JCA, JMS, and Web services "And tutorials" Introduction to the J2EE Connector Architecture . ")
J2EE Management Specification (JMX) for the J2EE platform, defines a model of information management. In accordance with its design, J2EE Management Model with a variety of management systems and interoperability agreement; contains the model to the Common Information Model (CIM) standard mapping, CIM is a SNMP Management Information Base (MIB); also can be a presence in the EJB components on the server - J2EE Management EJB Component (MEJB) - is mapped to the Java object model. (See " From black box to the enterprise, Part 1: Management, JMX 1.1 style . ")
Java Transaction API (JTA) is an independent and agreements to achieve high-level API, it allows applications and application servers can access the services. Java Transaction Service (JTS) specifies the realization of the Transaction Manager, which supports the JTA and the API layer to achieve under the OMG Object Transaction Service (OTS) 1.1 specification of the Java mapping. JTS using Internet Inter-ORB Protocol (IIOP) communications services. (See " Understanding JTS - An introduction to transactions . ")

J2ME technology:

Connected Limited Device Configuration (CLDC) is composed of resource-limited mobile information devices running the Java environment, one of two configurations. Description of the most basic CLDC libraries and virtual machine features, all contained in K Virtual Machine (K virtual machine, KVM) implementation of the J2ME environment must provide the Treasury and identities.
Mobile Information Device Profile (MIDP) is composed of resource-limited mobile information devices Java run-time environment, one of two configurations. MIDP provides the core application functionality, including user interface, network connectivity, local data storage and application life cycle management. (See tutorial " Implementing Push technology with J2ME and MIDP "; Read" Better MIDlets by design "" Custom GUI development with MIDP 2.0 "And tutorials" MIDlet development with the Wireless Toolkit . ")
Connected Device Configuration (CDC) is a standards-based framework can be used to build and delivery of inter-connected network of many consumer devices and embedded devices to share applications. (See " To ensure the safety of wireless J2ME . ")
Mobile 3D Graphics API for J2ME (M3G) is a lightweight, interactive 3D graphics API, as an optional package with a combination of J2ME and MIDP. (See the article in two parts " Java for 3D graphics for mobile devices . ")

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Java technology and SOA / Web services, the relationship between

Service-oriented architecture is a component model, which through the service interface between the definition of a good application and contract will be the functional unit (known as services, or Web services) linked. The way the definition is independent of interface hardware, operating systems and services used for the programming language, which makes the system in different services can be constructed to a common unified way to interact each other. SOA is a loosely coupled model, an alternative to more traditional tight coupling of object-oriented model.

Web services can be created using XML definition of business rules and processes so that software applications can be a platform-independent programming language and manner of communication. XML technology enables data portability and to facilitate the creation of messages, and Java technology with the portability of code. XML and Java language can be a very good combination, which makes them build and deploy the ideal combination of Web services.

Can learn more about the SOA Reference For more information:

developerWorks on the new SOA and Web services portal And XML new entry Page will help you get started learning these complex technologies.
" Java Web Services, Part 1: Java Web services in the development of the coming year "Article to start a series, this series introduced the new Java Web service framework and in building a Web services layer of the new features.
" SCA application development, Part 1: An overview of Service Component Architecture "Provided a concerning Service Component Architecture (SCA) of the article series, SCA is a specification that describes a use of SOA applications and systems to build the model.
" Service Data Objects Introduction "Introduced Service Data Objects (SDO) framework to simplify SOA-based applications Java EE programming model data.
Also be able to access developerWorks Web development area There are to build enterprise applications for the technical advice.

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Java technology and open source software development relationship

A large number of open-source project Through the database, tools, frameworks, applications and application server technology for the expansion of Java to help programmers make use of this powerful technology. Many open-source technology has been integrated into the Java platform itself, there are Java technology developers has been the favorite (in some cases has become the de facto standard).

Reference can learn more about programming aspects of Java open source technology:

Apache Software Foundation presided over this huge organization with a large number of open source projects, many of which are based on Java language. For example:
- Apache Struts is used to create based on the Model-View-Controller design pattern of the Java Web application framework. (See " Struts 1.1 in depth And Struts topic . ")
- Apache Shale is a technology based on JavaServer Pages modern Web application development framework, Apache Struts is a follow-up to those. ( Hello, Shale Article series introduced the Shale. )
- Apache Ant is a Java development tool to build a de facto standard. (See tutorial " Apache Ant 101: so easy to generate Java project "And" Programmatically call Apache Ant . ")
- Apache Tomcat is a popular Web container, which supports the servlet and JavaServer Pages technologies. (Guide " Tomcat for beginning Web developers "Will help you learn from Tomcat.)
- Apache Geronimo project is to build a completely open source-based components in full compliance with the norms of the Java EE application server. ( " Geronimo entry "Geronimo, introduced the basic knowledge, you can access developerWorks Apache Geronimo Project Resource Center Information of a large number of Geronimo. )
- Apache Derby is a full Java language using the relational database. (Through " Development with Apache Derby - been achieved victory: The Apache Derby "Learning the basic knowledge and access to developerWorks Apache Derby Project Reference The large amount of information. )
Eclipse is an independent manufacturer of open development platform, providing a set of software used to build the application framework. Eclipse platform is written using Java language provides a framework based on plug-ins, which makes the creation, integration and use of software tools easier. (IBM is a founding member of Eclipse, and the active participation of Eclipse.org Board of Stewards and the work of the subcommittee.) Through the following reference for further understanding of the Java platform's component technology development:
- AspectJ aspect-oriented extension of Java language can be used for cross-cutting concerns (such as logs and exception handling) to the modular. (See tutorial " AOP introduction . ")
- Standard Widget Toolkit (SWT) is a user interface tool kit, can be efficient and portable access to underlying operating system UI facilities. (See " SWT and JFace, Part 1: Introduction . ")
- Eclipse Test and Performance Tools Platform (TPTP) to test and performance tools and services provide a framework. (See tutorial " Eclipse Test and Performance Tools Platform Introduction . "
- Eclipse Web Tools Platform (WTP) for Eclipse provides a platform for the development of Java EE Web application tools. (See tutorial " Eclipse Web Tools Platform V1.0 Introduction . ")
Visit developerWorks Eclipse Project Resource Center There are a large number of articles on the Eclipse and tutorials.
Popular Spring framework for Java EE is an application development framework level:
- Spring Series And " About Spring 2 and JPA "Provide detailed information.
- Visit Spring topic Learn more about the Spring framework of articles and tutorials.

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How to improve their Java programming skills

Two lines can improve their skills: to attend a course (for certification or simply to learn) or self-study (of course, but also through the preparation of codes of practice). In addition to experience from the developer to obtain the knowledge, the courses or certification to the owner of the road can be a powerful proof that you have the skills they need. Carried out using a variety of self-reference, you can in all aspects of Java technology to improve your skills. The following reference materials for these two learning methods help:

Tutorials and articles
- developerWorks to provide a large number of Java-based practical course This is second only to their own code to prepare the best way of learning. Roy Miller's " Java Programming Introduction "And" Intermediate Java Programming "Guide for the Java language provides a comprehensive introduction to help you get started.
- Merlin's Magic And Tiger tamed Series can help improve your Java programming skills, excellent information.
- If you are a Java programmer has access to the C / C + + programmer, then " Java programming for C / C + + developers "Tutorial can help you speed up the learning rate, which compared the Java and C / C + + programming concepts.
- Extreme Programming (XP, XP) is an application design philosophy, it will continuously test first, on-site customer input, reconstruction (that is, to improve the code without changing the function) and so on together. If you have not heard of XP Essence , For the preparation of this article can provide a Java application outstanding tool. ( " Open the mystery of extreme programming: "XP essence" re-visit, part 2 "A detailed description of the practice.)
- Design theory into a practical application is Java Theory and Practice Series of focus.
- Java programmers can design integrated bug detection and testing applications. provided developerWorks Diagnosis of Java code Column discusses the Java debugger (to focus on a model of a tool known as the bug). On the subject help from the other articles, including the Brian Goetz Balance test The article, as well as " The elimination of bug . "
- You may have heard of called Ajax Programming method. If you want to know how to use Java developers of this technology, please read the series Phil McCarthy Java developer-oriented Ajax . (Please visit Ajax Technology Resource Center And Web 2.0 Development Resources , You can find more Ajax technologies to build Web 2.0 site with articles and tutorials)
Books and Web sites:
- " Java professionals required a list of books and websites "Is the best starting point.
Games
- Robocode is a Java technology used to build the easy-to-use robot simulator World War II, which teach you to program at the same time, can provide hours of pure entertainment. Robocode presentation on, please read " Heavy hammer blow Robocode! "; More, please visit The essence of Robocode column techniques .
- CodeRuler, CodeRally and CodeInvaders Challenge is built on the Eclipse platform, Java-based real-time programming game. On the introduction CodeRuler, please read " CodeRuler conquered by the Kingdom of the Middle Ages . "
IBM technical training
- IBM Global Services can provide a variety of online, classroom and multimedia-based Java courses Choose.
Certification training
- If you are considering for their Java skills to carry out certification, then a few exams to attend. To help you prepare for the exam, we have friends in the preparation of Whizlabs four parts of the curriculum " Java certification success ", The tutorial discusses the Sun Certified Java Programmer (SCJP) 1.4, Sun Certified Web Component Developer (SCWCD), Sun Certified Business Component Developer (SCBCD), and Sun Certified Enterprise Architect (SCEA). For the SCJP exam for Java SE 5 update Please read the article " Are you SCJP 5 certified? "." Preparing for the Mobile Application Developer Certification "Help you prepare for Sun Certified Mobile Application Developer (SCMAD).
- IBM in the WebSphere development (Java for enterprise applications), IBM Rational software, DB2, XML and SOA-related technology to provide Professional Certification .
Forum
- To a more interactive ways of learning the Java language, please take part in Java discussion forums Here brought together well-known experts in the use of Java technology has a wealth of practical experience.